1. The Field of the Invention
The present invention relates to the field of dentistry, and more particularly to endodontic cones, such as those made of gutta percha, used in filling root canal chambers.
2. The Relevant Technology
When a dental practitioner performs a root canal, pulp and other material in the root canal chamber is removed. Once a dentist has removed diseased and soft tissue from a tooth's root canal, the chamber must be filled. The purpose of filling the root canal is to seal the area, and to eliminate the possibility of bacterial attraction and infection in the chamber. Filling and sealing the chamber is necessary to prohibit material from draining into the canal, which could attract bacterial contamination of the root canal chamber. In addition, filling the chamber provides a base that may be drilled out later for placement of one or more posts to which may be mounted a crown or other restorative appliance.
The current method of filling the root canal is by inserting a shaped cone of gutta percha into the prepared root canal. Gutta percha typically includes a matrix of trans isoprene, zinc oxide filler, a radiopacifier such as bismuth, barium or strontium, wax or resin, color pigment, plasticizers and other additives.
One difficulty with using gutta percha has been that it does not readily bond to and seal against the tooth tissue. The tooth tissue is quite hydrophilic, while gutta percha itself is extremely hydrophobic. Typical endodontic pastes, used to bond and seal the gutta percha to the tooth tissue, comprise zinc oxide and eugenol. This mixture is hydrophobic, and while it bonds quite well to the gutta percha, its bonding to hydrophilic tooth tissue may often be poor. Recently, hydrophilic resins have been developed which bond much better to tooth tissue, but they may still bond poorly to gutta percha because of its extremely hydrophobic nature. The result may be a root canal chamber that is not completely sealed, which increases the chance of irritation of the affected area or bacterial contamination, leading to infection and possible failure of the root canal. The level of discomfort and pain associated with an irritated, inflamed, and/or infected root canal area can be great, followed by loss of the tooth.
For the foregoing reasons, there is a need for a root canal filling material and method which is able to provide a better bond and seal between the tooth tissue, any endodontic resin, and the gutta percha cone, giving better protection against irritation and infection than current materials and methods provide. The invention provides an adhesive gutta percha prepared by coating or dipping gutta percha into an adhesive material to yield an adhesive gutta percha that is able to bond to endodontic resins, including hydrophilic resins. The invention also provides related methods for use of the adhesive gutta percha.